216 (number)

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216 is the natural number following 215 and preceding 217.

Cardinal Two hundred [and] sixteen
Ordinal 216th
Factorization 2^3 \cdot 3^3
Roman numeral CCXVI
Binary 11011000
Octal 330
Hexadecimal D8

Since 216 = 33 + 43 + 53 = 63, it is the smallest cube that's also the sum of three cubes (Plato was among the first to notice this, and mentioned it in Book VIII of Republic). It is also the sum of a twin prime (107 + 109). But since there is no way to express it as the sum of the proper divisors of any other integer, it is an untouchable number.

This multiplicative magic square

\begin{pmatrix}
2 & 9 & 12\\
36 & 6 & 1\\
3 & 4 & 18
\end{pmatrix}

has magic constant 216.

In base 10, it is a Harshad number.

[edit] In other fields

[edit] See also

[edit] References

  • Wells, D. (1987). The Penguin Dictionary of Curious and Interesting Numbers (p. 144). London: Penguin Group.